Underground mines are required to provide ventilation raises, which may also serve as emergency escape raises through which underground miners can escape to the surface in the event of an emergency. For this purpose it is common for such underground escape raises to be provided with a ladderway to permit miners to climb up out of the mine. Conventional ladderways are typically in the form of a pre-fabricated steel ladder surrounded with a steel mesh caging to provide a measure of protection for the miners as they climb the ladder.
Apart from the fact that such steel ladderways are heavy and expensive to manufacture and install, they are also difficult and expensive to maintain. The ladderway is constantly exposed to groundwater and seepage which contribute to corrosion, particularly in highly saline groundwater conditions. Hence such steel ladderways require regular maintenance to ensure that salt and rust forming on the ladder rungs are cleaned away. It is difficult to ascertain to what extent the steel has corroded over time and the safety of the ladderway is compromised. Furthermore, the steel mesh cage does not provide adequate protection for miners from rock falls.
Commonly owned International Application No PCT/AU2005/001815 describes a ladderway system for an underground raise, the system comprising an elongate tube with a ladder mechanically coupled to an interior of the tube. The tube is of circular cross-section and is formed with a longitudinal slit along its entire length whereby the diameter of the tube can be adjusted to conform to the shape of the raise. Both the tube and the ladder are typically made from a suitable plastics material. The ladder is used for mounting both the ladder and the tube to a wall of the raise. Whilst this system operates quite well, it is rather cumbersome to install. Furthermore the manufacture and installation of the ladder and the tube as separate components detracts from the modular design of the system.
The present invention was developed with a view to providing an improved ladderway system that provides improved safety for miners escaping through a raise from an underground mine, but may also be applicable in other situations where a ladderway is required to provide an escape way in a relatively confined space.
References to prior art documents in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere.